1. Field of the Invention
The present invention relates to integrated circuits, and more specifically to a low noise output buffer suitable in several environments (e.g., to drive a transmission line which causes reflections).
2. Related Art
Output buffers are often used to drive external load (e.g., another integrated circuit or transmission line) based on data received from another source. In general, output buffers need to drive external loads with sufficient strength to ensure that the data is accurately transferred to the external devices within a pre-specified time duration.
One desirable feature of operation of output buffers is reducing noise. Noise generally refers to undesirable signal components present/introduced into a signal otherwise of interest. Reduction of noise generally leads to several advantages, as is well known in the relevant arts.
Noise can be introduced from a variety of sources. For example, switching noise generally refers to undesirable noise which is typically generated when there is transition of the signal at the output node (of the output buffer) from one value to the other.
There are other sources of noise as well. For example, when driving a transmission line (e.g., telephone line using DSL technology), the reflections may also introduce noise, which is again undesirable. Accordingly, it is generally desirable to provide output buffers which generate low noise.
In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.